The Association between Failure to Thrive or Anemia and Febrile Seizures in Children between 6 Months to 6 Years Old Age.

Objectives
Febrile seizure is the most common seizure disorder in childhood. Anemia or failure to thrive can predispose children to febrile seizure by affecting the nervous system function. The current study investigated the association between febrile seizures and anemia or failure to thrive.


Materials and Methods
This case-control study was performed on 307 children 6 months to 6 yr old age hospitalized at the Ali Asghar Children`s Hospital, Tehran, Iran from 2011 to 2014 divided into two groups as follows: A case group including 158 children with febrile seizures and a control group including 149 febrile children without seizure. The amount of Hgb, Hct, RBC count, MCV, MCH, and MCHC was recorded and weight-for-age and weight-for-height was calculated based on the WHO Z-Score charts. The data were compared between two groups.


Results
There were no differences regarding age and sex between the groups. Statistically significant differences were found regarding the mean RBC count between the case group (4.38×106 ± 0.72×106) and the control group (4.24×106 ± 0.84×106) (P=0.013), as well as about the mean MCV that was 78.73 ± 0.97 and 76.78 ± 1.00 in the case and control groups, respectively (P=0.005). Anemia was seen in 28.5% of the cases and 42.3% of control group which was statistically significant (P=0.012). There was not statistically significant difference regarding failure to thrive between two groups.


Conclusion
In children with febrile seizures, anemia was lower comparing with febrile children without seizure. Moreover, there was not any association between failure to thrive and febrile seizures.


Introduction
Febrile seizure is the most common seizure disorder during infancy and childhood and its incidence varies from 2%-14% in different populations (1). It occurs in the children older than one-month age with a febrile illness The Association between Failure to Thrive or Anemia and Febrile Seizures in Children between 6 Months... and without any central nervous system infection, acute electrolyte abnormality, or history of afebrile seizures (1). Some known risk factors of febrile seizures include positive family history of febrile seizures, attending the nursery for more than one month, developmental delay, going to kindergarten, sudden increase in body temperature, and maternal smoking (2,3).
Failure to thrive (FTT) can have different effects on the growing children such as secondary immunodeficiency, permanent damage to several parts of the central nervous system, and cognitive as well as developmental dysfunction (4). Its diagnosis will be raised if the child's physical growth is significantly lower than peers that is when the growth level is below the 3 rd or 5 th percentile or there is a drop in the growth rate to cut two percentile curves in a short time (4,5).
The prevalence of growth retardation depends on the sample population. In developed countries, 5%-10% of premature children and children with the lower socioeconomic status can have growth disorders. These statistics is much greater in developing countries with high rates of malnutrition and HIV infection (4,5). Trace elements affect many pathways and specific enzymes such as oxidative system in the central nervous system. Weakening of the antioxidative defense mechanisms and increased levels of free radicals can result to seizures (6). Thereby, electrolyte imbalances and deficiency of micronutrients such as zinc, selenium, magnesium, copper and vitamin D seen in the malnutrition and failure to thrive can predispose children to the febrile seizures (7-10).
Iron plays an important role in the neural activity, enzymatic reactions and metabolism of neurotransmitters (11). In developing countries, iron deficiency is the most common nutritional problem. its peak incidence is in the ages between 6 to 24 months old, which overlaps with the peak incidence of febrile convulsion that is in the ages from 14 to 18 months old (11,12). In these countries, 46%-66% of children less than four yr age have anemia that half of this prevalence is due to iron deficiency anemia (13). Anemia-defined as hemoglobin level below two standard deviations from normal values for age-affects the developing brain via changing seizures by the anemia have been discussed in many studies (13,14). While others have concluded that anemia does not predispose to febrile seizures and may even have a protective effect (16)(17)(18).
We investigated the relationship between the anemia or failure to thrive and febrile seizures to find out whether these prevalent health conditions could predispose the children to febrile seizures or not.

Materials and Methods
This case-control study was conducted on the  between the groups showed no significant differences. The Association between Failure to Thrive or Anemia and Febrile Seizures in Children between 6 Months...

Discussion
Results of our study showed that the prevalence of anemia in the febrile seizure group was significantly lower than the control group (28.5% versus 42.3%). This is identical with the results of another study that evaluated 51 febrile children 6-36 months old age in two groups (with and without seizure) for their iron status. Iron deficiency was less frequent in febrile seizure group. They suggested a probable relationship between iron deficiency and 7.8 fold decreased risk of febrile seizure (19). They stated that brain lipid peroxidation induced by iron may lead to febrile seizure. Moreover, cell membrane uptake and discharge of dopamine, gamma aminobutyric acid and other neurotransmitters may be affected by iron. Thereby, the seizure threshold may be increased due to iron deficiency (19). Although, a limited factor in their study was the small sample volume, the patients were well   (26).
In respect of the well-known influences of Our study demonstrated that anemia was seen less in children with febrile seizures. In addition, no relation was found between failure to thrive and febrile seizures.
Although in most studies on febrile seizures, as well as the current study, the control group had been selected from hospitalized patients with a febrile illness without convulsions, it seems that choosing the control group from outpatient febrile children with simple infectious diseases could provide a more reliable control group and more accurate results therefore.
In conclusion, according to contradictory results about the association between anemia and febrile seizures in various studies and the lack of enough studies regarding the effect of FTT on febrile seizures, further prospective and precise investigations in this respect is recommended.